This application relates to imaging systems for use in devices for use in minimally invasive or endoscopic surgery.
Endoscopic or minimally invasive surgery has become fairly common and is becoming more and more common as surgeons learn and advance endoscopic technology and techniques. Currently, endoscopic surgery is used for procedures conducted in the sinus cavities, on the spine, on knees, on feet, in the abdominal cavity, and in the thoracic cavity. As the technology (i.e., the surgical instruments) and techniques advance, endoscopic surgery will become even more prevalent.
Minimally invasive or endoscopic surgery, as is known, is conducted in a cavity within the patient's body. The cavity can be the patient's abdominal cavity, thoracic cavity, or a cavity formed using a tissue lifter. The cavity is closed. Hence, the surgeon is provided means to view the surgical site. In typical endoscopic procedures (such as conducted in the abdomen), an endoscope is used to provide lighting and to view the surgical site. The typical endoscope includes a stiff tube which is inserted into the patient cavity. The tube extends through the patient's tissue (i.e., through the abdominal wall for an abdominal procedure) and extends into the cavity. The end of the endoscope is spaced slightly from the inner surface of the cavity wall. Because of this spacing, the endoscope can pivot about the incision. If the endoscope pivots, the field of view changes. As can be appreciated, a changing field of view can adversely impact an ongoing procedure.
Imaging systems (such as stereotactical systems) have been provided, for example, for brain or cranial surgery. Such systems rely on a previously taken image and compare the previously taken image with a current image such that the surgeon can display the positioning of a surgical tool within the cranium. An example of such a system is described in U.S. Pat. No. 5,662,111. Such systems are acceptable for cranial surgery, where the surgical site is relatively immovable. However, in surgical sites, such as the abdominal or thoracic cavities, for example, where the tissues are softer and movement of the tissues at the surgical site or movement of the cavity wall during a procedure are likely, such stereotactical systems will not work well.